Still there:
https://www.chess.com/article/view/study-plan-directory
Yes I "cheated" and logged into V3 from the V2 study plan and no, I don't know how to find it from within V3, but I'm sure if you just click around for awhile...
Maybe try Articles?
I like the new site format but I miss the old "study plan" where we are offered suggestions of videos to watch,articles to read and drills to improve. Am I just not able to find it or was there a decision to eliminate it (too sad) I guess I am just too structured in my learning (at my age) not to miss that kind of organization. Anybody? :-)